Static time‐of‐flight secondary ion mass spectrometry and x‐ray photoelectron spectroscopy characterization of adsorbed albumin and fibronectin films

Abstract

Static time-of-flight secondary ion mass spectrometry (ToF-SIMS), monochromatized x-ray photoelectron spectroscopy (XPS) and 125 I radiolabeling have been used to characterize albumin films adsorbed onto titanium, gold, polytetrafluoroethylene and r.f. glow discharge-deposited tetrafluoroethylene (TFE) substrates. A comparison between albumin and fibronectin films also was made. The intensities of characteristic amino acid mass fragments (immonium ions) detected in the static ToF-SIMS experiments depended on the protein type, the substrate type and the adsorption conditions, demonstrating the sensitivity of static ToF-SIMS for probing the structure of adsorbed protein films. Based on the results from albumin and fibronectin, static ToF-SIMS can provide information about the identity of adsorbed proteins and their conformation, orientation, denaturation, etc. X-ray photoelectron spectroscopy can distinguish pure protein films, but the higher molecular specificity of static ToF-SIMS is more useful than XPS for examining complex protein films. The 125 I radiolabeling experiments and the XPS atomic percentage of nitrogen were used to quantify the amount of adsorbed protein.

Effects of Polythiophene Surface Structure on Adsorption and Conformation of Bovine Serum Albumin: A Multivariate and Multitechnique Study

“…22,24,28,34,57 Here we propose a more rigid approach, introduced by Monera et al, 58 that uses a relative measure of hydrophobicity of amino acid side chains. It is provided by the results of reversed phase chromatography (RPC) and defined as the difference in retention time, Δt R , relative to glycine peptide, of a peptide analogue differing only in one amino acid residue (substituted on the hydrophobic face of amphiphatic α-helix).…”

Nanomedicine for implants: A review of studies and necessary experimental tools

“…One important application of SIMS is to study the composition, conformation, orientation and denaturation of proteins on nanomaterial surfaces [50]. Protein adsorption is widely studied, but there still is little known about protein orientation and conformation after adsorption due to the characteristics of the surfaces and the complexities of protein structures.…”

Adsorption of BSA on passivated chromium studied by a flow-cell EQCM and XPS

“…6. The C 1s signal was fitted with three contributions corresponding to well identified carbon bonds present in the BSA molecule: the first peak named C 1 , at the lowest binding energy of 285.0 eV, is attributed to C-C, C C, and C-H; the second peak named C 2 , at 286.4 eV, is assigned to C-N and C-O single bonds; the third peak named C 3 , at 288.4 eV, is attributed to O C-O and O C-N (peptide bonds) bonds [2,31,32]. The curve fit parameters that were used for the C 1s XPS spectrum are given in Table 1.…”